It is commonly known that the participation in sporting activities such as basketball, tennis and the like which require running and instantaneous changes of direction can cause the athletic participant to develop blisters, callouses and other sores on the skin of the feet. This is primarily due to frictional shear forces between the skin layers. Foot blisters are also very common among athletes because of the excessive friction on the sole of the athletes foot at the maximum force points which are commonly under the metatarsal and under the large toe. Attempts have been made to overcome this problem through the use of pads and the like, commonly referred to as inner soles, placed in the athletes shoes. While the pads provide a horizontal cushion they do not eliminate transverse longitudinal friction on the sole of the foot which causes the blisters. Another attempt to solve this problem was proposed by Spence in U.S. Pat. No. 3,449,844. In that patent, an inner sole was taught comprising a closed cell foam such as neoprene which was covered with a two-way stretch fabric such as nylon. Although the elastic closed cell foam inner sole of U.S. Pat. No. 3,449,844 adequately accomplished the goal of reducing friction between the inner sole and skin resulting in decreased blistering and callousing, the inner sole nevertheless is not an ideal solution to improved comfort and wearability of shoes primarily intended for use in stress situations such as athletic events. It was found that an inner sole using only a closed cell foam base and fabric cover fails to possess the desired cushioning effect necessary in athletic use. Furthermore, a neoprene or equivalent material does not mold to the individual foot and maintain the contour of the foot as does the open cell material as taught herein.
It is thus an object of the present invention to produce an inner sole insert which eliminates all of the drawbacks outlined above.
It is the further object of the present invention to produce an inner sole insert which eliminates blistering and callouses due primarily to friction between the inner sole and the foot of the user.
It is yet another object of the present invention to produce an inner sole insert which cushions the foot and conforms to the shape of the foot and maintains that confirmation indefinitely.